In the technical field of life science or the like, it is common practice to disperse observation light (e.g., fluorescence or the like) from a specimen according to wavelengths and observe a plurality of optical images resulting from the dispersion. For example, Non Patent Literature 1 below discloses the dual view microscopy technique with a single camera, and describes this technique such that the observation light is dispersed by means of a light splitting assembly attached outside a microscope main body and that two observation beams resulting from the dispersion can be imaged with use of the camera. Patent Literature 1 and Patent Literature 2 below disclose the light splitting optical systems to be used in the dual view inspection technique.